Seat for a chair



FIG. 1 is a front, top perspective view of the seat for a chair showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a rear, side perspective view thereof; and,

FIG. 6 is a side elevation view thereof. 

CLAIM The ornamental design for a seat for a chair, as shown and described. 